Means for electrically locating mineral veins



(No Model.)

A. LIGHTHILL. MEANS FOR ELEGTRIGALLY LOCATING MINERAL VEINS.

'Patnted Dec. 9

UNITED STATES PATENT OFFICE.

AUGUST P. LTGHTHILL, OF BOSTON, MASSACHUSETTS.

MEANS FOR ELECTRICALLY LOCATING MINERAL VEIN S.

SPECIFICATION forming part of Letters Patent No. 308,908, dated December 9, 1884.

Application filed January 18, 1884. (N model.) i

To all whom it may concern:

Be it known that I, AUGUST 1?. LIGHTHILL, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain Improvements in Means for Electrically Detecting. Finding, and Locating Mineral Veins, of which the following is a specification.

My invention relates to certain improvements in electrical apparatus for detecting, IO finding, and locating veins and deposits of minerals which lie beneath the surface of the earth or of the water, and could ordinarily be only detected by the laborious and expensive process of boring or sounding. My devices permitsuch deposits to be located and their extent determined quickly and without boring or other expensive and difficult labor. My invention consists, briefly, of two metallic electrodes, preferably iron or steel,

adapted to be set upon or be forced into the ground and connected through a galvanometerkey and some source of electricity, preferably a battery.

The invention also consists in means for 2 5 converting the electrodes, when made of soft iron, into electro'magnets at pleasure.

The invention also consists in electro-magnets inserted into the above-described circuit, having polarized cores to secure more definite indications.

In the accompanying drawings, Figure l is a plan of my apparatus and the connections thereof, and showing the electrodes as permanent magnets, as inserted in the ground. Fig.

3 5 2 shows the electrodes as of soft iron and converted into electro-magnets. Fig. 3 shows a variation in the connections. Fig. 4 shows a variation in the form of the electrodes. Fig. 5 shows another variation.

0 In Fig. 1, Gis agalvanometer, which may be of the ordinary detector variety, but should be sensitive.

H H H H are electro-magnets having their cores polarized by contact with large perma- 4 5 nenthorseshoe-magnets M M,in a well-known manner.

151*" and E are electrodes, preferably of steel, permanently magnetized, the signs attached to their indicating-letters indicating '50 their reverse polarities. These electrodes are shown as partially inserted into the earth over a mineral vein, V.

' In Fig. l a current from the battery passes by wire 2 and magnets H H to electrode E. Then when .fed by a current from a mineral 5 5 vein, as hereinafter described, it will pass to electrode E from there by wire I, magnets H II, wire 2, galvanometer G, key K, and wire 2, back to battery. The keyK is an ordinary spring-key adapted to close a circuit on being depressed.

Having described my apparatus and connections thereof, I will now describe its practical operation, V V, Fig. 1, being intended to indicate mineral veins or deposits.

We will first suppose the electrodes E to be inserted into the earth at the point N, which is not near a mineral vein. Under these circumstances, the earth being dry, no current will pass and the galvanometer will be per- 7c fectly passive; but if the said electrodes be inserted at the point at which they are shown over vein V, a current will pass of sufificient strength to move the needle of the galvanometer perceptibly, the degree and rapidity of the movement depending on the size of the vein audits depth below the surface. I ascribe this to the presence of electric currents traversing mineral veins, which are generally of greater conductivity than the mass of the surrounding earth, and which currents are also generatedin such mineral deposits by the chemical changes thereof. I am forced to this conclusion because in practice I do not insert the electrodes until they touch the mineral deposit, as has been necessary in electric apparatus as hitherto employed in searching for ores, and then complete the circuit. On the contrary, I merely insert the electrodes a few inches into the ground, while the deposit in- 0 fluencing the galvanometer may lie many feet deep. This forms the great distinction between my method and all others hitherto invented. Iron, steel, or electrodes of some metal capable of being magnetized, are pref- 5 erable, and this because of the attraction exerted by the same upon the currents traversing the mineral deposits, the influence of a magnet, or even a bar of soft iron upon an electric current being well known. I find, 10o

2 I eoaaoe however, that brass, copper, or other nonmagnetic metals may be used for the electrodes; but in case non-magnetic metal is used the electrode should be pointed with iron or steel.

In my description of Fi 1, I have described permanently-magnetized steel electrodes, butin practice find soft-iron electrodes answer in most cases, because iron would attract a current itself, and also because, if inserted,as they naturally would be, vertically, the earths induction would magnctize them.

As it may be advantageous to polarize such soft-iron electrodes at pleasure, I show in Fig. 2 means for accomplishing this by winding helices O 0 around said electrodes near their upper ends, as shown, and a current-traverses said helices from battery B through wire 3 on depressing a key, li Fig. 2 also shows the end of an electrode as formed into a number of points, 0, to be inserted into the earth.

In Fig. at I show electrodes E-as fiat iron plates, to rest upon the surface of the earth. Said plates may have points 0 extending downward, as shown, or said points may be dis pensed with.

In Fig. 8 I show the connections through key K, thence by wire 2, galvanometer G, electroanagnets H H, (having cores polarized by large permanent magnets M BL) thence to electrode E, earth, and electrode 15*, and wire 2 to battery. By making the wires 1 and 2, which connect with the electrodes 15 E, into an insulated cable,the apparatus can be used 011 the bed of a lake or river. 7 If desired, the electrodes 15 E may be used. only with a battery, galvanometer, and key, as shown in Fig. 5, but not with such marked results as in the forms before described.

The described apparatus may be used to locate and find coal and other mineral veins, as well as those containing metals.

I also claim to be able to detect mineral oil and deposits or springs of water by the use of the described apparatus.

It will be observed that the electrodes are entirely independent of each other, so that they can be placed at any desired distance apart, or in any desired relation to each other.

It is obvious that any suitable indicatingsignal may be used instead of the galvanometer to indicate the presence of electric currents.

I claim 1. In an apparatus for detecting, finding, and locating mineral deposits, a battery or other source of electricity, a galvanonieter,

electrodes 15 E, helices H H H H, having polarized cores, and connections, as specified, whereby said battery, galvanometer, elec trodes, and helices are included in one and the same circuit.

2. In an apparatus for detecting, locating, and finding mineral veins, electrodes E E, formed of magnetizable metal, and connected through a battery and galvanometer, as specified, and helices G G, surrounding said electrodes,with connections through a battery and key, whereby said electrodes may be magnetized when desired.

3. The method of electrically detecting, locating, and finding mineral veins, which consists in applying the terminals of an electric circuit including indicating devices to the earths surface, but without contact with said veins, the presence or absence of said veins being shown by changes in the indicating apparatus.

it. The method of electricallydetecting and locating mineral veins, which consists in applying the terminals of an open electric circuit containing indicator devices to the earth,

but, not in contact with the said veins, the

presence or absence of said vein being indicated by the variations in the electric circuit due to the presence of said veins.

In testimony whereof I have signed my name to this specification,in the presence of two subscribing witnesses, this 14th day of January, 1884:.

AUGUST 1?. LIGHTHILL.

Witnesses:

C. F. Bnowlv, A. L. XVrrrrn. 

